Self adjusting wrench



Sept. 24, 1963 s. L. TRYBUs SELF ADJUSTING WRENCH 2 Sheets-Sheet 1 FiledAug. 22. 1960 :N HLH IN VENTOR STANLEY L. TRYBUS ATTORNEYS Sept. 24,1963 Filed Aug. 22. 1960 S. L. TRYBUS SELF ADJUSTING WRENCH 2Sheets-Sheet 2 FIG?. FIG.

INVENTOR STANLEY L. TRYBUS ATTORNEYS United States Patent O 3,104,571SELF ADJUSTING WRENCH Stanley L. Trybus, Omaha, Nebr., assignor toMueller Trybus Associates, Inc., Omaha, Nebr., a corporation of NebraskaFiled Aug. 22, 1960, Ser. No. 51,118 Claims. (Cl. 81-380) The presentinvention relates to self adjusting wrenches of the plier type and moreparticularly to such wrenches for gripping objects wherein the grippingjaws are automatically adjusted to the thickness of the object and inwhich the gripping force remains contant regardless of the thickness ofthe object to be gripped.

Heretofore various self adjusting plier-type Wrenches have been proposedwhich automatically `adjust for the thickness of the object to begripped within the range of sizes for which the wrench is designed.These wrenches apply a preselected gripping force to the objectregardless of thickness of the object and these structures preventslippage of the locking mechanism which otherwise might allow thegripping force to weaken with release of the object being gripped.

In these prior art devices a stationary jaw is provided having a shankforming a handle with Va movable jaw pivotally mounted on the shank ofthe stationary jaw; with a second handle pivotally connected to themovable jaw; with toggle linkage connecting the second handle with alocking Wedge attached to one end thereof; and with a second Wedgeadjustably mounted within the rst handle and positioned to coact withthe locking wedge. A spring is usually provided in the handle of thestationary jaw for urging the parts into operative positions. A link ofadjustable length is usually provided between the movable jaw and thesecond wedge to provide an approximate opening of the jaws for thethickness of the object to be gripped.

These prior art wrenches have certain disadvantages found primarily inthe rigidity of the link connecting the movable jaw and the second wedgewhich is subject to wear and breakage and, because of its rigidity,tends to distort and `spread the structure with which the second wedgeis associated. As a matter of fact, certain prior art devices employ thedistortion referred to in the structure adjacent the Wedges to allowsome further travel of the wedges together to permit the desiredgripping power to be locked onto the object and maintained on the objectduring thegripping thereof.

The present invention provides novel structure for eliminating the wearand breaking strain incident to a linkage of xed length between themovable jaw and the second wedge which, while accurately positioning thesecond Wedge during the gripping operation, permits the linkage, ineffect, to be compres-sed after the wedges have locked together topermit further gripping movement of the jaws without strain and breakageof the 4linkage or distortion of the tool assembly.

It is therefore the object of the present invention to provide a novelstructure for a self adjusting wrench of the plier type in which thelinkage between the movable jaw land its :associated wedge is manuallyadjustable in length to determine the initial opening of the jaws and toposition the associated wedge and, thereafter, during the grippingmovement of the jaws the linkage can move with respect to its wedge toshorten its effective length to prevent breakage of the linkage anddistortion of the associated part of the wrench.

One embodiment -of the novel construction of the present concept isillustrated in the accompanying drawings and is described hereinafter inexplanation of the invention. 'Ihis illustrative embodiment should in noway be construed as deiining or limiting the invention.

3,104,571 Patented Sept. 24, i963 ICC In the accompanying drawings, inwhich like reference characters indicate like parts, FIG. l is a `sideelevational view of an illustrative embodiment of a wrench incorporatingthe present invention;

FIG. 2 is a view from above of the embodiment of FIG. 1;

FIG. 3 is a sectional view of the Wrench shown in FIG. 1 on the line3--3 of FIG. 2 but with the jaws engaging an object;

FIG. 4 is -a cross sectional view of the wrench of FIG. l on the line4-4 thereof;

FIG. 5 is a cross sectional view on the line 5-5 of FIG. l;

FIG. 6 is a cross sectional view on the line 6 6 of FIG. 1;

FIG. 7 is a cross sectional View on the line 7--7 of FIG. l; and

FIG. 8 is a cross sectional view on the line 8-8 of FIG. l.

With reference now to the several figures, the wrench is seen tocomprise Ia fixed jaw 10' having a hollow U-shaped extension forming abody portion 11 and a handle l2. Movable jaw 13 is mounted on pivot 14within body 11. Handle l5 which is hollow and U-shaped in cross sectionis pivoted at 16 to movable jaw 13. Link i7 is pivoted in handle 15 atl8r. Wedge y19 which is hollow carries pivot 2o on which link 17 ismounted. Wedge 19 is carried by iiap 21 extending between the sides ofhandle 12.

Link I7 is apertured at 22 to receive one end of expansion spring 23 andthe other end of expansion 23 is mounted in aperture 24 in jaw 13. Link17 is provided with a flat surface 25 for engagement with the innersurface of handle l5 when pivots 16, 1S, and 2t)` are in approximatelythe same straight line when handle 15 is moved toward lhandle 12 tocause rotation of jaw 13 toward jaw 10 and toward the gripping of anobject.

A pivot 26 is mounted on jaw 13 opposite pivot 16 and a threaded link 27is rotatably mounted thereon. A manually actuable adjusting nut 28 ismounted on the threads of link 27. A second link 29 is provided withthreaded end 3@ which is threaded into nut 28 and has nut 31 mountedthereon. Spring 32 surrounds link 29 behind nut 3l and engages Washer 33which is received against shoulder 34 of wedge 35. Wedge 35 is suitablyshaped to be received within handle 12 and for lock-ing engagement withwedge 19. Wedge 35 is `cut away -at 36 to receive spring 32 and isrecessed at 3-7 to Ireceive Y slotted end 3S of link 29. Pin 39 ismounted in wedge 35 .and extends through slot 38 of link 29. Spring 32acts to engage pin 39 in the left end of slot 33 as shown in FIG. 3. Nut31 is adjustable along threads 30 to provide the desired compression ofspring 32.

With this construction is will be seen that rotation of nut 2S to movelinks 27 and 29 into nut 28 will close jaws 13 and 1t) ultimately to theposition shown in FIG. l when handle 15 engages surface 25 of link 17.It follows that rotation of nut 28 adjusts the spacing of jaws l0 and11. Handles l2 and l5 are then opened with respect 4to each other end,with the object to be gripped centered between jaws 13 and 10, handles15 and 12 are moved toward each other. Movement of handle 15 towardhanle l2 rotates link 17 `against the action of spring 23 :and moveswedge 19 to the left as seen in FIG. 3 within the housing formed by flap21. Rotation of jaw 13 toward jaw 10 moves the linkage made up of link27, nut 28, link 29 and spring 32 and associated wedge 35 to the left asseen in FIG. 3 since, to all intents and purposes at this point, thislinkage arrangement is solid and unyielding. Movement yof wedges 19 and35 to the left continue until they come into locking engagement whichoccurs before handle 15 engages surface 25 of link 17.

Further movement of handle 15 toward handle 12 to move jaws 13 and 10into iirm gripping engagement on the object to be gripped would nowstrain the linkage between jaw y13 and wedge 35 and distort the wrenchassembly but for the presence of spring 32, slot 38 and pin 39. Duringthe final stages of the gripping engagement of jaws 13 and 10 on theobject to be gripped, spring 32 compresses and slot 38 rides over pin 39until surface 25 of link 17 comes into engagement with handle 15. Atthis point maximum gripping action is provided on the object by jaws and13, wedges 19 and 35 are firmly locked in position and no movement ofjaws 10 and 13 can take place until 'handle 15 is moved relatively awayfrom handle 12.

It follows that this structure provides a novel spr-ing loaded linkageto position the adjustable wedge 35 of the wrench which then allows thelinkage to, in eiect, change tits length when handle 15 places pressureon movable jaw 13 of the wrench during ythe dnal gripping movement ofjaw 13 with respect to jaw 10.

It should now be apparent that the objectives of the present inventionare obtained by the above described illustrative embodiment thereof.

Changes in or modifications to the described illustra- .tive embodimentof this invention may be now suggested to those skilled in the artwithout departing from the invention and reference should therefore behad to the appended claims to determine the scope thereof.

What is claimed is:

1. In a' wrench having an elongated handle forming a body portion with astationary jaw, a coacting movable jaw p-ivoted to the body portion, asecond handle pivoted to the movable jaw, a link pivoted to the secondhandle and to a wedge slidably mounted in the elongated handle, a secondWedge slidably mounted in the elongated handle coacting with the firstwedge and linkage connecting the second wedge and the movable jaw, saidlinkage including means movable with respect to the second wedge underpredetermined force `for decreasing the eiective length of said linkagewhen the wedges are in set posi- Y tion in the elongated handle and themovable jaw isv moved toward the stationary jaw.

2. In a wrench as described in claiml,V said means i including a secondlink engaging and mounted for limited, movement with respect to thesecond wedge and resilient resilient means between the link and themovable jaw,-

said linkage means including a second link, an elongated slot at one endof said second link, a pin in said slot mounted in said second Wedge, aspring urging said second link away from said pin, threads on the otherend' of said second link, a manually rotatable nut on said threads, athird link pivoted to the movable jaw and threads on said third linkengaged in said nut.

5. In a wrench as described in claim 1, said means including a secondlink connected for limited movement.

to the second wedge, resilient Ameans urging said second link away fromthe second wedge, a manually actuated nut mounted on said second linkand a third link extending between said nut and the movable jaw.

References Cited in the tile of this patent UNITED STATES PATENTS2,500,590 Ward et al Mar. 14, 1950 2,531,285 Manspeaker Nov. 21, 19502,595,579 Hawkins May 6, 1952 2,751,801 Hostetter .T une 26, 19562,814,222

Sanders Nov. 26, 1957

1. IN A WRENCH HAVING AN ELONGATED HANDLE FORMING A BODY PORTION WITH ASTATIONARY JAW, A COACTING MOVABLE JAW PIVOTED TO THE BODY PORTION, ASECOND HANDLE PIVOTED TO THE MOVABLE JAW, A LINK PIVOTED TO THE SECONDHANDLE AND TO A WEDGE SLIDABLY MOUNTED IN THE ELONGATED HANDLE, A SECONDWEDGE SLIDABLY MOUNTED IN THE ELONGATED HANDLE COACTING WITH THE FIRSTWEDGE AND LINKAGE CONNECTING THE SECOND WEDGE AND THE MOVABLE JAW, SAIDLINKAGE INCLUDING MEANS MOVABLE WITH RESPECT TO THE SECOND WEDGE UNDERPREDETERMINED FORCE FOR DECREASING THE EFFECTIVE LENGTH OF SAID LINKAGEWHEN THE WEDGES ARE IN SET POSITION IN THE ELONGATED HANDLE AND THEMOVABLE JAW IS MOVED TOWARD THE STATIONARY JAW.